I have what is hopefully the last update to this mess, the dealer screwed up, what a surprise...

So after my call to Subaru Canada, a rep showed up a the dealer and they, according to the service person, we there on another unrelated reason and “put their heads together” and discovered that the machine shop they sent the valves/heads out to a machine shop and they ground down the valves/heads or something (a thing they normally don’t do). So when the dealer went the put it all back together they didn’t check whether the valves/heads were machined down and that screwed up things in the cylinder causing the vibration that’s been happening all along.

All in all, the dealer has admitted it’s they’re fault and are fixing it at no charge to us. Now I just need to get an answer if there’s a warranty on any of this work they’re doing.